1. Field of the Invention
This invention relates generally to electrical wiring distributing floor structures, and more particularly to improvements in a closure member presented at the surface of such a floor structure, wherein a seal is provided around the wires egressing from the closure member.
2. Description of the Prior Art
It is a common practice to provide plural preset inserts throughout the floor area of an electrical wiring distributing floor structure. Each preset insert is intended to provide access to plural electrical services. When activating a preset insert, an activating assembly is provided which includes a closure member presented at the surface of the floor structure. Connections to the electrical services are made within the preset insert with the wires egressing through the cover.
In order to maintain the fire resistance rating of the floor structure, the areas around the wires egressing from the cover, must be sealed. One method of obtaining the required seal is to field-cut holes in the cover which closely fit the emerging wires, see for example U.S. Pat. No. 3,932,696 (FORK et al). In addition, a strip of fire resistant material can be placed within the interior of the preset insert to shield the upper portion of the preset insert and the cover from heat transfer by convection and by radiation, see U.S. Pat. No. 4,324,078 (GRAY). The main disadvantage of the FORK et al.'696 and GRAY'078 arrangements is that a new cover member must be installed in either of two circumstances. That is where a connection is broken and the wire is removed leaving an unfilled hole in the cover member; or where a wire of lesser diameter egresses through a previously cut, larger diameter hole in the cover member.
Flush floor fittings are known wherein the overlying carpeting surrounds the emerging wires, see U.S. Pat. No. 4,237,666 (KOHAUT). The KOHAUT'666 arrangement is directed to the aesthetic appearance of the carpeting in the area of each preset insert. The KOHAUT'666 reference is not concerned with the fire resistance of the floor structure.
A closure member is known having a retractable access port which is positionable between a closed position wherein the port is flush with the cover member and an open position wherein the port projects upwardly from the cover member to allow egress of wiring, see Catalog No. 85725-1 entitled "MULT-A-CELL II", issued in 1985 by MIDLAND-ROSS CORPORATION. The retractable access port is provided with a dust seal said to be formed from a foam plastomer. The MIDLAND-ROSS publication does not discuss the affect of the foam plastomer dust seal on the fire resistance of the floor.